FIG. 1 shows a data transmission network according to the state of the art. An IP backbone is connected via a broad-band data transmission line to a main switch such as an xDSL line termination device. The main switch is connected to several xDSL network termination devices NT over xMII interface. The NT is connected via a UTP telephone line to a local switch or hub which distributes the data packages received from the main switch to different data communication devices such as a personal computer or a laptop or an IP phone via a CAT5 communication line. The switch and the data communication devices form a local area network (LAN), e.g. an Ethernet local area network. The Ethernet local area network according to the state of the art does not allow data exchange between data communication devices and the local switch via an ordinary CAT3 copper telephone line over home telephone topology which requires its own wiring structure besides the telephone lines which are already installed in a building.